A 10-day-old preterm neonate (born at 32 weeks gestation) on mechanical ventilation develops fever, thrombocytopenia, and positive blood cultures growing Coagulase-negative Staphylococcus (CoNS) from a central line. What is the drug of choice for presumed late-onset neonatal sepsis due to CoNS?

Explanation

## First-Line Therapy for Late-Onset Neonatal Sepsis (CoNS) **Key Point:** Vancomycin is the drug of choice for late-onset neonatal sepsis (LOS) caused by Coagulase-negative Staphylococcus (CoNS), particularly in the setting of central venous catheters. ### Late-Onset Sepsis (>72 hours of life) — Epidemiology LOS pathogens differ markedly from EOS: - **Coagulase-negative Staphylococcus** (most common, 30–40%) — especially in NICU, associated with central lines - **Staphylococcus aureus** (including MRSA) - **Candida species** (in preterm infants) - **Gram-negative organisms** (Klebsiella, Pseudomonas, Serratia) - **Enterococcus** ### Why Vancomycin? 1. **Excellent coverage of Gram-positive cocci:** - CoNS (often methicillin-resistant) - MRSA - Streptococcus species 2. **Penetration into CNS** — important if meningitis is suspected 3. **Biofilm formation** — CoNS on catheters are often resistant to beta-lactams; vancomycin achieves intracellular and biofilm concentrations ### Neonatal Vancomycin Dosing | Age | Dose | Interval | | --- | --- | --- | | 0–7 days | 15 mg/kg/dose | Q12h | | >7 days | 15–20 mg/kg/dose | Q8–12h (depends on renal function) | **Clinical Pearl:** Therapeutic drug monitoring (TDM) is essential in neonates. Target trough levels: **10–15 μg/mL** (higher if meningitis). Immature renal function necessitates longer intervals and frequent level checks. ### Empiric Regimen for LOS Vancomycin + **Cefotaxime** (or Meropenem) is the standard empiric combination for LOS until culture results clarify the organism. Once CoNS is confirmed, vancomycin monotherapy is sufficient. **High-Yield:** CoNS is the #1 cause of LOS in NICU patients, especially those with central lines (umbilical or PICC). Vancomycin is the standard of care because many CoNS strains are methicillin-resistant. **Mnemonic:** **CONS-V** — Coagulase-negative Staph = Vancomycin [cite:Nelson Textbook of Pediatrics 21e Ch 121, AAP Neonatal Resuscitation Program]